func (s *SelectList) resolveAggFields() { for i, v := range s.Fields { if expression.ContainAggregateFunc(v.Expr) { s.AggFields[i] = struct{}{} } } }
// CheckAndUpdateSelectList checks order by fields validity and set hidden fields to selectList. func (r *OrderByRset) CheckAndUpdateSelectList(selectList *plans.SelectList, tableFields []*field.ResultField) error { for i, v := range r.By { if expression.ContainAggregateFunc(v.Expr) { expr, err := selectList.UpdateAggFields(v.Expr, tableFields) if err != nil { return errors.Errorf("%s in 'order clause'", err.Error()) } r.By[i].Expr = expr } else { names := expression.MentionedColumns(v.Expr) for _, name := range names { // try to find in select list // TODO: mysql has confused result for this, see #555. // now we use select list then order by, later we should make it easier. if field.ContainFieldName(name, selectList.ResultFields, field.CheckFieldFlag) { // check ambiguous fields, like `select c1 as c2, c2 from t order by c2`. if err := field.CheckAmbiguousField(name, selectList.ResultFields, field.DefaultFieldFlag); err != nil { return errors.Errorf("Column '%s' in order statement is ambiguous", name) } continue } if !selectList.CloneHiddenField(name, tableFields) { return errors.Errorf("Unknown column '%s' in 'order clause'", name) } } } } return nil }
// GetAggFields gets aggregate fields position map. func GetAggFields(fields []*field.Field) map[int]struct{} { aggFields := make(map[int]struct{}, len(fields)) for i, v := range fields { if expression.ContainAggregateFunc(v.Expr) { aggFields[i] = struct{}{} } } return aggFields }
// CheckAndUpdateSelectList checks having fields validity and set hidden fields to selectList. func (r *HavingRset) CheckAndUpdateSelectList(selectList *plans.SelectList, groupBy []expression.Expression, tableFields []*field.ResultField) error { if expression.ContainAggregateFunc(r.Expr) { expr, err := selectList.UpdateAggFields(r.Expr, tableFields) if err != nil { return errors.Errorf("%s in 'having clause'", err.Error()) } r.Expr = expr } else { // having can only contain group by column and select list, e.g, // `select c1 from t group by c2 having c3 > 0` is invalid, // because c3 is not in group by and select list. names := expression.MentionedColumns(r.Expr) for _, name := range names { found := false // check name whether in select list. // notice that `select c1 as c2 from t group by c1, c2, c3 having c2 > c3`, // will use t.c2 not t.c1 here. if field.ContainFieldName(name, selectList.ResultFields, field.OrgFieldNameFlag) { continue } if field.ContainFieldName(name, selectList.ResultFields, field.FieldNameFlag) { if field.ContainFieldName(name, tableFields, field.OrgFieldNameFlag) { selectList.CloneHiddenField(name, tableFields) } continue } // check name whether in group by. // group by must only have column name, e.g, // `select c1 from t group by c2 having c2 > 0` is valid, // but `select c1 from t group by c2 + 1 having c2 > 0` is invalid. for _, by := range groupBy { if !field.CheckFieldsEqual(name, by.String()) { continue } // if name is not in table fields, it will get an unknown field error in GroupByRset, // so no need to check return value. selectList.CloneHiddenField(name, tableFields) found = true break } if !found { return errors.Errorf("Unknown column '%s' in 'having clause'", name) } } } return nil }
// CheckAggregate will check whether order by has aggregate function or not, // if has, we will add it to select list hidden field. func (r *HavingRset) CheckAggregate(selectList *plans.SelectList) error { if expression.ContainAggregateFunc(r.Expr) { expr, err := selectList.UpdateAggFields(r.Expr) if err != nil { return errors.Errorf("%s in 'having clause'", err.Error()) } r.Expr = expr } return nil }
// CheckAggregate will check whether order by has aggregate function or not, // if has, we will add it to select list hidden field. func (r *OrderByRset) CheckAggregate(selectList *plans.SelectList) error { for i, v := range r.By { if expression.ContainAggregateFunc(v.Expr) { expr, err := selectList.UpdateAggFields(v.Expr) if err != nil { return errors.Errorf("%s in 'order clause'", err.Error()) } r.By[i].Expr = expr } } return nil }
// CheckAndUpdateSelectList checks order by fields validity and set hidden fields to selectList. func (r *OrderByRset) CheckAndUpdateSelectList(selectList *plans.SelectList, tableFields []*field.ResultField) error { for i, v := range r.By { if expression.ContainAggregateFunc(v.Expr) { expr, err := selectList.UpdateAggFields(v.Expr, tableFields) if err != nil { return errors.Errorf("%s in 'order clause'", err.Error()) } r.By[i].Expr = expr } else { if _, err := selectList.CheckReferAmbiguous(v.Expr); err != nil { return errors.Errorf("Column '%s' in order statement is ambiguous", v.Expr) } // TODO: check more ambiguous case // Order by ambiguous rule: // select c1 as a, c2 as a from t order by a is ambiguous // select c1 as a, c2 as a from t order by a + 1 is ambiguous // select c1 as c2, c2 from t order by c2 is ambiguous // select c1 as c2, c2 from t order by c2 + 1 is ambiguous // TODO: use vistor to refactor all and combine following plan check. names := expression.MentionedColumns(v.Expr) for _, name := range names { // try to find in select list // TODO: mysql has confused result for this, see #555. // now we use select list then order by, later we should make it easier. if field.ContainFieldName(name, selectList.ResultFields, field.CheckFieldFlag) { continue } if !selectList.CloneHiddenField(name, tableFields) { return errors.Errorf("Unknown column '%s' in 'order clause'", name) } } } } return nil }
// Plan gets GroupByDefaultPlan. func (r *GroupByRset) Plan(ctx context.Context) (plan.Plan, error) { fields := r.SelectList.Fields r.SelectList.AggFields = GetAggFields(fields) aggFields := r.SelectList.AggFields for i, e := range r.By { if v, ok := e.(expression.Value); ok { var position int switch u := v.Val.(type) { case int64: position = int(u) case uint64: position = int(u) default: continue } if position < 1 || position > len(fields) { return nil, errors.Errorf("Unknown column '%d' in 'group statement'", position) } index := position - 1 if _, ok := aggFields[index]; ok { return nil, errors.Errorf("Can't group on '%s'", fields[index]) } // use Position expression for the associated field. r.By[i] = &expression.Position{N: position} } else { index, err := r.SelectList.CheckReferAmbiguous(e) if err != nil { return nil, errors.Errorf("Column '%s' in group statement is ambiguous", e) } else if _, ok := aggFields[index]; ok { return nil, errors.Errorf("Can't group on '%s'", e) } // TODO: check more ambiguous case // Group by ambiguous rule: // select c1 as a, c2 as a from t group by a is ambiguous // select c1 as a, c2 as a from t group by a + 1 is ambiguous // select c1 as c2, c2 from t group by c2 is ambiguous // select c1 as c2, c2 from t group by c2 + 1 is ambiguous // TODO: use visitor to check aggregate function names := expression.MentionedColumns(e) for _, name := range names { indices := field.GetFieldIndex(name, fields[0:r.SelectList.HiddenFieldOffset], field.DefaultFieldFlag) if len(indices) == 1 { // check reference to aggregate function, like `select c1, count(c1) as b from t group by b + 1`. index := indices[0] if _, ok := aggFields[index]; ok { return nil, errors.Errorf("Reference '%s' not supported (reference to group function)", name) } } } // group by should be an expression, a qualified field name or a select field position, // but can not contain any aggregate function. if e := r.By[i]; expression.ContainAggregateFunc(e) { return nil, errors.Errorf("group by cannot contain aggregate function %s", e.String()) } } } return &plans.GroupByDefaultPlan{By: r.By, Src: r.Src, SelectList: r.SelectList}, nil }
// Plan gets GroupByDefaultPlan. func (r *GroupByRset) Plan(ctx context.Context) (plan.Plan, error) { fields := r.SelectList.Fields resultfields := r.SelectList.ResultFields srcFields := r.Src.GetFields() r.SelectList.AggFields = GetAggFields(fields) aggFields := r.SelectList.AggFields for i, e := range r.By { if v, ok := e.(expression.Value); ok { var position int switch u := v.Val.(type) { case int64: position = int(u) case uint64: position = int(u) default: continue } if position < 1 || position > len(fields) { return nil, errors.Errorf("Unknown column '%d' in 'group statement'", position) } index := position - 1 if _, ok := aggFields[index]; ok { return nil, errors.Errorf("Can't group on '%s'", fields[index].Name) } // use Position expression for the associated field. r.By[i] = &expression.Position{N: position} } else { names := expression.MentionedColumns(e) for _, name := range names { if field.ContainFieldName(name, srcFields, field.DefaultFieldFlag) { // check whether column is qualified, like `select t.c1 c1, t.c2 from t group by t.c1, t.c2` // no need to check ambiguous field. if expression.IsQualified(name) { continue } // check ambiguous fields, like `select c1 as c2, c2 from t group by c2`. if err := field.CheckAmbiguousField(name, resultfields, field.DefaultFieldFlag); err == nil { continue } } // check reference to group function name indices := field.GetFieldIndex(name, fields[0:r.SelectList.HiddenFieldOffset], field.CheckFieldFlag) if len(indices) > 1 { // check ambiguous fields, like `select c1 as a, c2 as a from t group by a`, // notice that `select c2 as c2, c2 as c2 from t group by c2;` is valid. if r.HasAmbiguousField(indices, fields[0:r.SelectList.HiddenFieldOffset]) { return nil, errors.Errorf("Column '%s' in group statement is ambiguous", name) } } else if len(indices) == 1 { // check reference to aggregate function, like `select c1, count(c1) as b from t group by b + 1`. index := indices[0] if _, ok := aggFields[index]; ok { return nil, errors.Errorf("Reference '%s' not supported (reference to group function)", name) } } } // group by should be an expression, a qualified field name or a select field position, // but can not contain any aggregate function. if e := r.By[i]; expression.ContainAggregateFunc(e) { return nil, errors.Errorf("group by cannot contain aggregate function %s", e.String()) } } } return &plans.GroupByDefaultPlan{By: r.By, Src: r.Src, SelectList: r.SelectList}, nil }